Anyone here ever started a Photo Agency or Coop before?

The subject is too complicated to cover on a site like this. But suffice it to say, creating an agency won’t get you business that you could not get on your own. And, it takes a lot of capital to start one.

In all seriousness, an agency is no stronger than its members. Really talented photographers can usually get in to see photo buyers (editorial or commercial). For them, an agency will not improve that. On the other hand, it can also bring down their standing if lesser quality photographers are in the agency.